The safety benefits of limiting ISA: a pilot study using real world crash situations

Abstract

Limiting Intelligent Speed Adaptation (ISA) is an in-vehicle technology that seeks to eliminate speeding by limiting the speed of the vehicle to the speed limit. This report describes a pilot study that assesses a particular method of evaluating limiting ISA using real world crashes and information from event data recorders (EDRs). The EDR files and additional details regarding the crash were obtained from the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from the United States of America (USA). A small sample of 59 cases from 2013 was used in this pilot study. It was estimated that, with limiting ISA, 13 of these could be avoided completely, serious injury crashes could be reduced by 62%, and moderate injury crashes by 22%. It was concluded that limiting ISA may have the potential to produce large reductions in injuries, though these may be smaller in jurisdictions with superior speed compliance. The study also found that less than 10% of EDR files within the NASS-CDS database were suitable and that use of EDR data can restrict the crash types and vehicle types in the sample. However, EDR data that is suitable appears to be more accurate and complete than that from alternative sources like crash reconstructions. It is recommended that a full study of this type be undertaken using a larger sample of EDR data from the NASS-CDS database and that the feasibility of an Australian EDR database matched to injury data should be investigated. In a full study, methods to reduce the time taken to identify suitable cases with the NASS-CDS database should be investigated.